Electric ignition assembly for liquid fuel burners



Jan. 3, 1961 J. L. BREESE 2,966,943

ELECTRIC IGNITION ASSEMBLY FOR LIQUID FUEL BURNERS Filed Feb. 11, 1957 2Sheets-Sheet 1 (D o o o N (D o o Q 0 o o In 0927292" N Jomzas Z BreeseJ. L. BREESE Jan. 3, 1961 ELECTRIC IGNITION ASSEMBLY FOR LIQUID FUELBURNERS Filed Feb. 11, 1957 y far/re?" a? drier Jito 7 72 ey-S UnitedStates Patent ELECTRIC IGNITION ASSEMBLY FOR mourn FUEL'BURNERS James L.Breese, Santa Fe, N'. Mex., assignor, by mesne assignments, to ControlsCompany of America, Schiller Park, lll., a corporation of Delaware FiledFeb. 11, 1957, Ser. No. 639,268

3 Claims. (Cl. 158-91) This invention is directed to animproved-electrical ignition assembly for hydroxyl'ating pot-type.liquidfuel-type burners. A major purpose of. the present invention isthe provision of an improved electrical ignition. assembly which resiststhe formation of carbon-like tar on a resistance heating element in thistype of burner ignition assembly..

Another purpose of the present inventioniis the provision of an improvedignition assembly which generates a balanced mixture of combustible gasfor ignition.

Another purpose of the present invention is the provision of improvedelectrical ignition means for pot-type liquid fuel burners which is soformed as to allow the location of a gasifying device at a locationremote from the base of the burner pot.

Another purpose of the present invention is the provision of an.improved burner pot electrical ignition assembly that may be readilyserviced and which also provides for lighting the burner manually in theevent of a power failure.

Another purpose of the present invention. is to provide a combinedliquid fuel delivery and electric ignition assembly for use withhydroxylating pot-type. liquid fuel burners, which can be used as the.fuel supply of liquid fuel to the interior of the pot, both at the timeof ignition and at all subsequent stages of combustion.

Other purposes will appear in the ensuing specification and claims.

Referring generally now to the drawings:

Figure 1 is a side elevational view of the improved burner pot andignition assembly constituting the present invention; and

Figure 2 is an enlarged detail view in section of the improved ignitionassembly constituting the present invention.

Like elements are designated by like characters throughout thespecification and drawings.

Referring specifically now to the drawing and in the first instance toFig. 1, 1 designates a more or less conventional pot-type liquid fuelburner It may have a plurality of vertically spaced rows of primary andsecondary air inlet apertures in the wall thereof as is well known tothe art. According to the present invention, an ignition tube 2 isaffixed to the wall of the burner pot as by welding and communicatesthrough an aperture 3 in the pot with the interior of the burner pot. Itshould be noted that the tube 2 is inclined to the horizontal.

The outer end of the tube is closed by a cap 4 that fits over the end ofthe tube and has a rim 5 embracing the outer Wall of the tube. The outerwall of the tube may be screw threaded as at 6 so as to provide apassageway for exterior air into the interior of the tube in response toa draft imposed on the burner pot. Positioned centrally of the end ofcap 4 is a support 7 which may be cylindn'cally formed. A hollow tube 8is positioned centrally of the support 7 and is mounted thereon as byspacers 9 and 9a. The hollow tube 8 serves to conduct 2,966,943 PatentedJan. 3, 1961 2. exterior air from a generally cylindrical chamber 10 tothe interior of the ignitor. Chamber 10 maybe defined by a closedcylinder on the end of cap 4. An air inlet 11 supplies air to thechamber 10.

A generally cylindrical gasifier 12 is affixed to the support 7. Thegasifier 12 is preferably formed from three super-imposed wraps of wiremesh screen. The lower end of the gasifier 12 is afiixed to an extension13 from the support 7. The upper end of the gasifier 12 is supported onthe body of the support proper. The extension 13 may be formedas apartly cylindrical member extending from the body of the cylindricalsupport 7.

A resistance heating element 14 has one end afiixed to the extension 13and the other end is supplied with electrical. energy through anysuitable lead (not shown). The. lead' may, for example, be broughtthrough the spacer 9a for connection to the inner end 15 of the heating.element 14. The electrical connections do not form part of the. presentinvention and for this reason, they are not shown in the drawing. Thearrangement shown permits a variety of electrical connections which willbe known to those skilled in the art.

A fuel inlet nozzle 16 is mounted on the upper portion of the tube 2 andis adapted to supply liquid fuel from a. conduit. 19 and source (notshown) to the gasifier 12. The nozzle 16 directs liquid fuel in the formof? a jet stream against the gasifier 12. It should be noted that theextension 13 is opposed to the nozzle 16 so as to prevent a directpassage of fuel through the. heating element. 14. The extension 13 actsto divert fuel sprayed on to the gasifier in. a generallycircumferentially extendvarious. positions in the upper portion of thetube 2 between the nozzle 16 and the end cap 4. 'If desired, one or moreadditional air inlets 18 may be formedv in the tube 2 at a positionbetween. the burner pot 1 and the nozzle 16. Y

Whereas I. have shown. and described the operation of my invention, IWish it to be understood? that this showing and description thereofshould be taken in an illustrative or diagrammatic sense only. There aremany modifications to the invention which will fall within the scope andspirit of the invention and which will be apparent to those skilled inthe art. The illustration and description of the invention should betaken in an illustrative or diagrammatic sense only and not in anylimiting sense. The scope of the invention should be limited only by thescope of the hereinafter appended claims.

The use and operation of my invention is as follows:

I illustrate an electrical ignition assembly for hydroxylating liquidfuel pot-type burners. The assembly is so formed that the gasifier 12 islocated at a remote position with respect to the base of the burner potwhich, during use of the pot, may contain a body of fuel. The gasifier12 is positioned upwardly and away from this body of fuel in the base ofthe burner pot. This tends to eliminate the carbon and coking conditionthat exists in a wick and heating element when the ignitor dips into thefuel poolat the base of a burner pot.

When ignition is desired, resistance heating element 14 is energized anda jet stream of oil is delivered against the gasifier 12. Air forcombustion is supplied through the tube Z'and towards the burner pot 1,both on the inside of the gasifier 12 and the outside thereof. Air issupplied through the tube 8 and through the interior of the gasifier. Atthe same time air is supplied along the exterior of the gasifier fromthe inlet 17 and from gasifier adjacent the nozzle and too lean on theinterior of the coil. Somewhere between these extremesthere is a placein which the gas air mixture is perfect for low temperature ignition.

When ignition is initiated the flame is directed downwardly into theburner pot. Any excess fuel from the nozzle 16 runs down the tube 2 intothe pot where it is vaporized during the combustion process. The sameassembly may be employed for delivering fuel to the pot both duringignition and during normal combustion. After ignition and when thecombustion process takes place within the burner pot, the nozzle 16 maycontinue to deliver fuel against the gasifier 12 from whence it proceedsto the base of the burner pot. Thus the nozzle 16, with suitable flowcontrol means, not herein shown, may be employed to supply all theliquid fuel necessary to maintain combustion within the pot at allstages, from ignition to high fire. v

By using three Wraps of screen wire for the gasifier I provide anoptimum amount of screen mesh for the gasification of the fuel.

By using the jet stream of oil against the screen mesh gasifier theresistance heating element 14 can operate at or near the theoreticalignition temperature of a dry gas which is several hundred degrees lowerthan the softening temperature of ordinary Nichrome coils. Thus withthis type of ignition ordinary changes in line voltages will hold theignitor coil safely between the lowest ignition temperature and thehighest melting temperature of the coil.

In the event power fails, ignition of the pot may be initiated manuallyby merely removing the cap 4 from the end of tube 2, initiating the jetstream of oil and lighting the same with a lighted wad of paper whichmay be dropped into the tube 2. The end cap 4 and ignition assembly maythen again be placed over the end of the tube 2 after combustion is thusinitiated. The tube 2 is threaded as at 6 to receive a cap whereelectric ignition is not desired and normal ignition with a torch is tobe used (not shown in the drawing).

The jet stream delivered against the gasifier provides instant ignitionfor the burner and this tends to provide a faster burner warmup.

I claim:

1. In a combined liquid fuel delivery and electric ignition assemblyadapted for use with hydroxylating pot type liquid fuel burners, adownwardly inclined tube having an open lower end, a cylindricalpervious vaporizing screen element spaced in said tube above said openlower end, supporting means for the screen element including a tubularstructure extending along the axis of the tube from the outer end of thetube, an electric heating means spaced within said screen element andmeans for energizing it for and thereby increasing the temperatureadjacent said screen element, a liquid fuel nozzle positioned on theside of said tube and formed and adapted to direct a jet of liquid fuelinto the interior of said tube and against the exterior of saidvaporizing screen element, a shield means interposed between theelectric heating means and the liquid fuel nozzle, an axial air inletductpositioned to deliver air to.the space surrounded by the vaporizingscreen at a zone adjacent the electric heating means, and a partialclosure for the'upper end of the tube formed and adapted to permit airleakage into the interior of the tube.

2. The structure of claim 1 further characterized in that said shieldmeans shields the electric heating means from impingement of the fueljet, while permitting such jet to contact the vaporizing screen element.

3. The structure of claim 2 further characterized by a plurality of airinlet apertures in said tube generally adjacent the ends of said screen.

References Cited in the file of this patent UNITED STATES PATENTS

